Field
The present disclosure relates to a persimmon leaf-derived polysaccharide fraction possessing immuno-stimulating and antitumor effects and a preparation method thereof.
Discussion of the Background
Persimmon leaves contain vitamin C of which content is 20 times higher than a lemon, and thus are used as health herbal tea. Persimmon leaves have the benefits of facilitating blood circulation, strengthening blood vessels, and being effective against scurvy, anemia, heart diseases, arteriosclerosis and cerebral hemorrhage. However, there have been little or no studies on the effects of persimmon leaves on the immune system.
Human beings have their own healing power which facilitates the overcoming of diseases naturally without external intervention. The tendency of increasing occurrence of various diseases in modern society is due to decrease in human healing power. However, human healing power has been weakening gradually since humans in modern society tend to depend on medications even for trivial conditions.
Immunity means the differentiation between self and non-self and the self-defense capability of a subject against both internal and external enemies. Health can be maintained through the immune system by which external enemies such as bacteria and viruses and internal enemies such as dead cells and abnormal cells among new cells derived from gene replication can be eliminated. Hence, it is natural that decreased immune function leads to an increased susceptibility to diseases. Further, immune function generally weakens along with aging.
In order to overcome any dysfunction of immune system, a variety of immune function stimulators have been developed and utilized. However, upon being used in long term, those substances tend to cause adverse side effects depending on different immunity in each individual. Particularly, while prevention is more important than treatment in immune-related diseases, currently available therapeutics are not suitable for the prevention of immune-related diseases. Therefore, there exists a strong need for natural therapeutics without adverse side effects.
Natural materials known to be involved in the activation of the immune system include lentinan isolated from Lentinus edode, polysaccharide K (PSK) isolated from Coliolus versicolar and so on.
Macrophages are the cells which secrete various cytokines and regulate immune conditions during the process of engulfing and digesting microorganisms and foreign substances, along with their pivotal role as an immune function against antigens. Macrophages are involved with antigen presentation and non-specific immune function of lymphocytes, in combination with their direct cytotoxicity on tumor cells. Furthermore, it has been reported that materials responding to TLR (Toll-like receptor) such as LPS or natural substances may activate macrophages, leading to the proliferation of T and B cells, the stimulation of macrophages for phagocytosis, and the production of cytokines such as IL-1, IL-6, IL-10, IL-12 and TNF-α known to regulate the secondary immune function against the infection of microorganisms.
Natural killer (NK) cells function to directly attack and kill cancerous cells or virus-infected cells through various mechanisms. These NK cells make up a small portion (5-10%) of total lymphocytes, but are the first responder with a potent capability to sense and remove abnormalities such as mutations in normal cells. In addition, NK cells, which are innate immune cells, play a very important role in regulating the functions of other immune cells and stimulating acquired immune cells to perform more potent defense action.